Respiratory Histopathology Flashcards
What does VITAMIN CDEF stand for?
Vascular
Infective/ Inflammatory
Trauma
Autoimmune
Metabolic
Iatrogenic
Neoplastic
Congenital
Degenerative
Endocrine/ environment
Functional
What are the important lung diseases you need to know?
COPD
Asthma
Chronic bronchitis
Respiratory failure
Pneumonia
Tuberculosis
Bronchiectasis
Cystic fibrosis
Lung cancer
Mesothelioma
URTI
Carcinoma of the larynx
What is pulmonary oedema?
Accumulation of fluid in alveolar spaces as consequence of “leaky capillaries” or “backpressure” from failing left ventricle
Poor gas exchange = hypoxia = respiratory failure
Summarise the important parts of pulmonary oedema
Often associated with heart failure (acute or chronic).
Very common cause of acute and chronic respiratory failure in A&E and community, and common finding at post mortem.
What are the causes of pulmonary oedema?
Left heart failure
Alveolar injury (drugs, inhalation, infection, pancreatitis)
Neurogenic - head injury
High altitude- altitude sickness
What is the pathology of pulmonary oedema?
Acute: Heavy watery lungs, intra-alveolar fluid on histology
Chronic: Iron laden macrophages, fibrosis
What causes ARDS in adults?
V- Blood transfusion, DIC, Shock
I- Infection (local or generalised sepsis), Pancreatitis
T- Aspiration, Trauma, Inhaled irritant gases
M- Drug overdose
Idiopathic
What causes hyaline membrane disease of newborn?
Insufficient surfactant production
Premature babies
What is Acute lung injury pattern/Diffuse alveolar damage?
Important cause of rapid onset respiratory failure – difficult to treat, patients end up on ICU
Caused by acute damage to endothelium and/or alveolar epithelium
Basic pathology is the same in all = Diffuse alveolar damage
What does diffuse alveolar damage cause?
Lungs are expanded and firm
Plum coloured, airless
Often weigh >1kg
What is the outcome of diffuse alveolar damage?
Death ~ 40%
Superimposed infection
Resolution : Lung returns to normal
Residual fibrous scarring of lung : Chronic respiratory impairment
Summarise the definition, epidemiology and presentation of asthma
Chronic inflammatory airway disorder with recurrent episodes widespread narrowing of the airways that changes in severity over short periods of time.
Prevalence increased in recent decades >10% children, 5% adults
Presents with wheezing, chest tightness, SOB, night-time cough
In a severe attack patients develop status asthmaticus.
What are the causes of asthma?
Atopic: genetic tendency to develop allergic reaction to common environmental allergen (e.g. house dust mites)
Non-atopic
Air pollution
Drugs - NSAIDs
Occupational – inhaled gases/fumes
Diet
Genetic factors
Physical exertion – “cold”
Intrinsic
What are the acute and chronic changes of asthma?
Acute change
Bronchospasm, oedema, hyperaemia, inflammation
Chronic change
Muscular hypertrophy
Airway narrowing
Mucus plugging
How does COPD present?
Very common cause chronic respiratory failure. May present with acute (often infective) exacerbations
What causes COPD?
~80% are smokers
Smoking causes inflammation and secondary damage to airways and interstitium
What is he pathology of COPD?
Mix of airway and alveolar pathology (chronic bronchitis and emphysema), resulting in progressive airway obstruction
What is chronic bronchitis?
Chronic cough (and inflammation) productive of sputum Most days for at least 3 months over at least 2 consecutive years
What is the pathology of chronic bronchitis?
Dilated airways
Mucus gland hyperplasia
Goblet cell hyperplasia
Mild inflammation
What are the complications of COPD/ chronic bronchitis?
Infections
Respiratory failure
Pulmonary HTN
Right sided HF
Lung Cancer
What is emphysema?
A permanent loss of the alveolar parenchyma distal to the terminal bronchiole
What is the pathophysiology of emphysema?
Cigarette smoking causes reduced Alpha 1 antitrypsin and other antiproteases as well as inflammation (neutrophil and macrophage activation)
This increases proteases in the lung which causes tissue damage
What is the histological difference between smoking and alpha 1 antitrypsin deficiency?
Smoking- Loss centred on bronchiole - CENTRILOBULAR
Alpha 1 antitrypsin deficiency- Diffuse loss of alveolae - PANACINAR
What are the complications of emphysema?
Large air spaces (bullae)
Rupture - pneumothorax
Respiratory failure
Pulmonary hypertension and right sided heart failure.
What is bronchiectasis?
Permanent abnormal dilatation of bronchi with inflammation and fibrosis extending into adjacent parenchyma
Where does bronchiectasis occur?
Variation in site depending on cause (idiopathic often involves lower lobe)
What does bronchiectasis cause?
Inflamed scarred lungs with dilated airways
What are the causes and associations of bronchiectasis?
Inflammatory
Congenital
What are the inflammation related causes of bronchiectasis?
- Infection
- Post-infectious (especially children or cystic fibrosis)
- Abnormal host defense 1º [hypogammagl.] and 2º [chemotherapy, NG]
- Ciliary dyskinesia 1º [Kartagener’s] and 2º
- Obstruction (extrinsic/intrinsic/middle lobe syn.)
- Post-inflammatory (aspiration)
- Secondary to bronchiolar disease (OB) and interstitial fibrosis (CFA, sarcoidosis)
- Systemic disease (connective tissue disorders)
- Asthma
What are the complications of bronchiectasis?
Recurrent infections
Haemoptysis
Pulmonary Hypertension and right sided heart failure
Amyloidosis
What is cystic fibrosis epidemiology?
Affects 1 in 2,500 live births
Autosomal recessive (approx 1/20 of population are heterozygous carriers)
Chr 7q3 = CFTR gene (Cystic Fibrosis Transmembrane Conductance Regulator) = chloride ion transporter protein. >1400 mutations, but commonest Delta F508
What is cystic fibrosis?
Abnormality leads to defective ion transport across cell membranes leading to excessive resorption of water from secretions of exocrine glands.
What is affected in CF?
Generalised disease of exocrine glands resulting in abnormally thick mucus secretion - affects all organ systems.
GI tract -> meconium ileus, malabsorption
Pancreas -> pancreatitis, malabsorption
Liver -> cirrhosis
Male reproductive system -> infertility
Lung
What lung infections do you get in CF?
Over 90% of patients have lung involvement:
- Recurrent infections (P.aeruginosa, S.aureus, H. influenzae, B.cepacia)
- Haemoptysis, Pneumothorax, Chronic respiratory failure and cor pulmonale, Allergic bronchopulmonary aspergillosis (ABPA), Atelectasis, BRONCHIECTASIS
How do you treat CF?
Improved treatment (physio, antibiotics, enzyme supplements /creon/, parenteral nutrition) has led to survival often into fourth decade
Lung transplantation offers longer survival
What can cause pulmonary infections?
Bacterial, including mycobacteria
Viral
Mycoplasma
Fungal & parasitic – think if history of foreign travel
Opportunistic infections (CMV, Pneumocystis, fungal) - think if history of immunosuppression
What are the symptoms of pulmonary infections?
Shortness of breath, cough, fever, purulent sputum
What are the most common organisms that cause pulmonary infections in:
- The community
- Hospital
- Aspiration
Community acquired: streptococcus pneumoniae, haemophilis influenzae, mycoplasma
Hospital acquired: gram –ve (klebsiella, pseudomonas)
Aspiration: Mixed aerobic and anaerobic
What are the patterns of pulmonary infections?
Bronchopneumonia
Lobar pneumonia
Abscess formation
Granulomatous inflammation
What is bronchopneumonia pathology?
Pathology - Patchy bronchial and peribronchial distribution, often lower lobes
When does bronchopneumonia happen?
Compromised host defense - Elderly
Often low virulence organisms - Staphylococcus, Haemophilius, Streptococcus, Pneumococcus,
What is the histopathology in bronchopneumonia?
Peribronchial distribution
Acute inflammation surrounding airways and within alveoli
What is and what causes lobar pneumonia?
Acute bacterial infection of a large portion of a lobe or entire lobe.
Infrequent with advent of antibiotics
90-95% pneumococci (S. pneumoniae)
Widespread fibrinosuppurative consolidation
What is the histopathology of lobar pneumonia?
- Congestion
Hyperaemia
Intra-alveolar fluid - Red hepatization
Hyperaemia
Intra-alveolar neutrophils - Grey hepatization
Intra-alveolar connective tissue - Resolution
Restoration normal architecture.
What are complications of lung infection?
Abscess formation
Pleuritis and pleural effusion
Infected pleural effusion (EMPYEMA)
Fibrous scarring
Septicaemia
What is a granuloma?
Collection of histiocytes/macrophages +/- multinucleate giant cells
Necrotising or non necrotising
What causes caseating granulomas?
TB- Fairly common in urban community and immunosuppressed.
Other causes include fungi and parasites
History of foreign travel
What causes atypical pneumonia?
Mycoplasma, viruses (e.g. CMV, influenza), Coxiella, Chlamydia
What is the result of atypical pneumonia?
Interstitial inflammation (pneumonitis) without accumulation of intra-alveolar inflammatory cells
Chronic inflammatory cells within alveolar septa with oedema +/- viral inclusions
What is a pulmonary thromboembolus?
Occlusion of pulmonary artery by thromboembolus
What may occur just prior to a pulmonary embolus?
Common site formation in deep veins of leg (95%)
Present with swelling of leg (DVT)
Present with symptoms of spread to lung (pulmonary embolism)
What is virchows triad in relation to PE?
factors promoting blood stasis
damage to endothelium
increased coagulation
What are the RFs for a PE?
Advanced age, female sex, obesity, immobility, cardiac failure, malignancy, trauma, surgery, childbirth, haemoconcentration, polycythaemia, DIC, contraceptive pill, cannulation, anti-phospholipid syndrome.
What are the effects of a PE based on size?
Small peripheral pulmonary arterial occlusion
Haemorrhagic infarct
Repeated emboli cause increasing occlusion of pulmonary vascular bed and pulmonary hypertension
Large emboli can occlude the main pulmonary trunk (saddle embolus)
Sudden death, acute right heart failure, or cardiovascular shock occurs in 5% of cases when >60% of pulmonary bed is occluded
How may a patient present with PE?
Patients present with pleuritic chest pain or chronic progressive shortness of breath due to pulmonary hypertension
Sudden death, acute right heart failure, or cardiovascular shock occurs in 5% of cases when >60% of pulmonary bed is occluded
If patient survives, the embolus usually resolves
30% develop second or more emboli
What causes a non thrombotic embolus?
Bone marrow
Amniotic fluid
Trophoblast
Tumour
Foreign body
Air
What new disease exists in 2019?
Vaping associated acute lung injury